The present invention relates to an apparatus and a method for locking and ejecting a pen device, such as an input pen used for inputting information into a computer-based device.
Portable electronic devices such as personal digital assistants (PDAs) have become increasingly popular. They are lightweight and they embody an array of useful functions, such as, electronic computation and personal information management, all of which are typically provided by desktop computer systems. Portability of these devices has been greatly enhanced by using a display assembly, consisting of a touch panel (or contact-sensitive panel) and a Liquid Crystal Display (LCD), for performing both input and output functions. This eliminates the need to carry another input device, such as a keyboard or a pointing device such as a mouse, or both.
Instead, an input device such as an input pen (or stylus) is used. A user typically contacts the tip of an input pen (or stylus) on the touch panel. By exerting adequate pressure on the touch panel via the pen tip on target images (or icons) displayed on the LCD screen or dragging the pen tip on the touch panel with designated strokes, the user is able to perform navigation, selection and typing functions conveniently.
As the input pen is lightweight and compactly elongated, it is usually stowed within the housing of an electronic device. Most devices use a mechanical locking mechanism to lock the pen during stowing, and a mechanical ejecting mechanism to eject the pen from its housing. An example of such a locking mechanism features a constriction embedded within the pen housing, which engages an annular groove on the pen to lock it. An example of a mechanical ejecting mechanism includes a compressed spring which when released, urges the pen out of the housing. The user then pulls the protruding end to remove the pen.
Such mechanical locking and ejecting mechanisms cause mechanical wear and tear on the pen, on the locking mechanism as well as on the ejection mechanism. As an alternative to having an ejection mechanism, a recess may be built into the opening of the pen housing to allow a user""s fingers to comfortably grip a sufficiently protruding end of a stowed pen and pull to remove the pen. During stowing, a protruding pen risks its being caught onto clothes and thereby having the clothes accidentally remove the pen from its housing, whereas an additional recess built into the surface of the device reduces the aesthetic appeal of the device.
Accordingly, there is a need to depart from mechanical locking and ejecting mechanisms and arrive at a desirable apparatus and method for locking and ejecting an input pen.
The present invention provides a method and apparatus for locking (or retaining) and ejecting a removable device, such as an input pen (or stylus). The present invention uses mutual electromagnetic attraction or repulsion to respectively lock or eject an input pen from its pen housing within a portable electronic device such as a PDA. Alternatively, mutual electromagnetic attraction and repulsion are used to respectively lock or eject a pen housing within the device, for displacing the input pen.
To this end, the apparatus provides a pen housing to hold a pen in a locked or retained position, a locking means to lock the pen and a releasing-ejecting means to release and to eject the pen from the pen housing. To eject the pen, a user activates a switch to operate a circuit for generating a magnetic force to eject the pen from its housing. To lock the pen into the pen housing, the user inserts the pen into its housing. The pen is retracted and locked in the housing by a mutually attractive magnetic force.
Instead of ejecting the pen, a movable pen housing is alternatively ejected within the device. To this end, the apparatus provides a movable pen housing to hold a pen in a locked position, a locking means to lock the pen and a releasing-ejecting means to release and to eject the pen housing. The ejection of the pen housing is limited by the device casing within which the pen housing is housed. One end of the ejecting pen housing hits an inner wall of the device casing and comes to a rest within the device. At the same time, the pen is carried by the ejecting movement such that one end of the pen sufficiently protrudes from the portable device for gripping and removing by a user. To lock the pen in the pen housing, the user inserts the pen into the pen housing. The pen is retracted into the housing and both the pen and the pen housing are locked or retained by a mutually attractive magnetic force.